Valle, G and Crisma, M and Toniolo, C and Rao, Sudhanand RB and Sukumar, M and Balaram, P (1991) Stereochemistry of peptides containing 1-aminocycloheptane-1-carboxylic acid (Ac-c). In: International Journal of Peptide & Protein Research, 38 (6). pp. 511-518.
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The crystal structures of four peptides incorporating 1-aminocycloheptane-1-carboxylic acid (Ac7c) are described. Boc-Aib-Ac7c-NHMe and Boc-Pro-Ac7c-Ala-OMe adopt beta-turn conformations stabilized by an intramolecular 4----1 hydrogen bond, the former folding into a type-I/III beta-turn and the latter into a type-II beta-turn. In the dipeptide esters, Boc-Aib-Ac7c-OMe and Boc-Pro-Ac7c-OMe, the Ac7c and Aib residues adopt helical conformations, while the Pro residue remains semi-extended in both the molecules of Boc-Pro-Ac7c-OMe found in the asymmetric unit. The cycloheptane ring of Ac7c residues adopts a twist-chair conformation in all the peptides studied. 1H-NMR studies in CDCl3 and (CD3)2SO and IR studies in CDCl3 suggest that Boc-Aib-Ac7c-NHMe and Boc-Pro-Ac7c-Ala-OMe maintain the beta-turn conformations in solution.
|Item Type:||Journal Article|
|Additional Information:||Copy right of this article belongs to MUNKSGAARD INT PUBL LTD.|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit|
|Date Deposited:||26 Apr 2010 08:18|
|Last Modified:||19 Sep 2010 06:00|
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